1. Field of the Invention
The present invention relates to Q-switching-induced gain-switched erbium pulse laser system, and more particularly, to an laser system employing a Q-switch component to Q-switch an Er3+-doped gain medium, and induce a gain-switched pulse from the Er3+-doped gain medium at the wavelength region from 2.5 μm to 3.0 μm.
2. Description of Related Art
Laser, i.e., light radiation with a narrow range of frequencies, is a collimated, monochromatic, and coherent beam produced by stimulated emission amplification and feedback resonance. It is also well-known that the “resonance structure”, the “gain medium” and “pumping light source” of three essential requirements must be used for generating a laser.
Moreover, since a laser beam has many advantages in optical properties, the laser beam is widely applied in many technical fields. For example, because water molecules absorb photons within the range of wavelength 2.5 μm to 3.0 μm, the laser beam in the wavelength region can be properly applied in the Biological or Medical field (e.g., cell cauterization and cutting in surgery).
In conventional techniques, generally, the laser pulse within the 2.5 μm to 3.0 μm wavelength region is achieved by employing the conventional active bulk Q-switches. However, the conventional laser system that employs the active bulk Q-switches has disadvantages of large volume, difficulty of optical alignment and high cavity loss.
Compared to the actively pulsed laser system, the passively pulsed laser system has many advantages as compactness, low cost and simple integration with fiber lasers. Moreover, an all-fiber laser structure has the advantages of high efficiency, largely accumulatable gains, exemption for optical alignment, convenient packaging, low cavity loss, small volume, high flexibility, and high quality laser beams of single mode. In addition, the all-fiber laser structure has the diameter of the output mode in micro-scale, so that the outputting laser beams have high photon density.
For the above-mentioned reason, a passively pulsed all-fiber laser system has many advantages over the actively pulsed bulk laser systems. Thus far, a fiber-type saturable absorber Q-switch at this mid-IR range of 2.5-3.0 μm has not been developed for erbium ZBLAN fiber lasers. Hence, it is desirable to provide a novel passive laser system generating laser pulses within the 2.5 μm to 3.0 μm wavelength region.
Therefore, it is desirable to provide a laser system with an Q-switch component that can Q-switch an Er3+-doped gain medium so as to generate gain-switched erbium pulses at the wavelength region within the 2.5 μm to 3.0 μm.